The present invention relates to an improvement in a structure of a heating sheet, in which protective covers are formed on both surfaces of a sheet-like heater element and the periphery thereof is bonded.
A conventional heating sheet is known in which protective covers are arranged at both surfaces of a sheet-like heater element and the periphery thereof is bonded. However, in a conventional heating sheet of this type, the position of the heater element sandwiched between the protective covers cannot be seen from the outside. This results in inconvenience when the heating sheet is to be mounted on equipment such that the heater element will not contact such equipment.